The notorious "crazy ants," Paratrechina longicornis, are well known for their seemingly nonsensical zig-zag swarms while carrying heavy loads. A recent study in Nature Communications demonstrates that the wild paths of these longhorn ants actually have a purpose.
As it turns out, the ants are taking turns filling different roles; some carry the heavy load while others "scout out' the surroundings by running in seemingly purposeless paths. (check out the video at this link, or this youtube video!) So what looks like deadbeat ants frolicking around where their companions carry is actually a nuanced rotating task distribution system.
These individual scouts are continuously bringing back small pieces of information to the load-carriers; further, the roles are continually and quickly changing between individuals. That is, there aren't just a few leaders-- instead, each ant fills the role of "leader" at some point.
The authors write "Contrary to some species that rely on the information and guidance of a single or few leaders ... cooperative transport in P. longicornis ants is more distributed. Small amounts of information continuously enter the system as carriers detach from the load and make room for the attachment of informed individuals that correct the steering."
The authors add,
"...our model suggests that P. longicornis ants continuously balance conformism with individuality to optimize collective performance."
Kind of like a gaggle of middle schoolers choosing what outfit to wear.
But "they're not stupid at all," says Feinerman, also a researcher at the Weizmann Institute of Science. (Also learn about: The Genius of Swarms.) They found that the ants rotate jobs, alternating between carrying the load and "scouting out" the scene. If any scout ants notice their loaded down comrades drift off course, they grab hold and stubbornly push the disoriented group back on track. (Learn about more real-life animal superpowers.)